Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)
Dec. 6, 2018 at 2:15 p.m. in Gernot-Graeff-Raum, Staudinger Weg 7, 05-431Univ-Prof. Dr. Jure Demsar
Univ.-Prof. Dr. Hans-Joachim Elmers
Univ.-Prof. Dr. Mathias Kläui
Univ.-Prof. Dr. Thomas Palberg
Multiferroics permit the magnetic control of the electric polarization and the electric control of the magnetization. These static magnetoelectric (ME) effects are of enormous interest: The ability to read and write a magnetic state current-free by an electric voltage would provide a huge technological advantage. Dynamic or optical ME effects are equally interesting, because they give rise to unidirectional light propagation as recently observed in several multiferroic compounds [1-5].
In conventional media the propagation of waveslight, magnons and phononsis reciprocal, that is counter-propagating waves experience the same material properties. However, reciprocity can be violated in multiferroic materials, where the velocity and the attenuation depend on the ±k direction of the wave propagation [1]. Such non-reciprocal propagation can be the consequence of e.g. the dynamic magnetoelectric effect emerging in materials with simultaneously broken time reversal and spatial inversion symmetries. Recently, the non-reciprocal wave propagation has also been observed in multi-antiferroics [6], i.e. in materials with coexisting purely antiferroelectric and antiferromagnetic orders. The symmetry-based guidance for the synthesis of multi-antiferroics and the connection to antiferromagnetic spintronics will also be discussed.